Ginsenoside Rb1 inhibits the carotid neointimal hyperplasia induced by balloon injury in rats via suppressing the phenotype modulation of vascular smooth muscle cells.

This study aims to investigate the effects of ginsenoside Rb(1) on vascular intimal hyperplasia in rats and explore the mechanisms. The rat vascular neointimal hyperplasia model was made by rubbing the endothelia of carotid artery with a balloon and Rb(1) (10 and 30 mg/kg/day) was given the day after surgery for 14 consecutive days. The neointimal hyperplasia level and the degree of vascular smooth muscle cells (VSMCs) proliferation were evaluated by histopathology and by calculating the proliferating cell nuclear antigen (PCNA) positive expression percentage; protein expressions of PCNA, phosphorylation extracellular signal-regulated kinase 1/2 (pERK1/2), smooth muscle α-actin (SM α-actin), and the mRNA expressions of proto-oncogene c-myc, SM α-actin, SM-emb (embryonic smooth muscle myosin heavy chain) and p38 MAPK were detected by immunohistochemistry and Real Time RT-PCR, respectively. Compared with the endothelia rubbing model group, Rb(1) 10 and 30 mg/kg/day medication significantly ameliorated the neointimal hyperplasia (P<0.05), and decreased the positive expression percentage of PCNA(P<0.05). Rb(1) medication also significantly decreased the elevated protein expression of pERK1/2 and the mRNA expression of c-myc(P<0.05), and tended to reduce the expression of p38 MAPK mRNA. Endothelial rubbing increased the SM-emb mRNA expression, but decreased the expression of SM α-actin mRNA which was reversed by Rb(1) (P<0.05). The results indicate that Rb(1) inhibits the vascular neointimal hyperplasia induced by balloon-injury in rats via suppressing the VSMC proliferation, which may be involved in part the inhibition of pERK1/2 protein and related to its inhibition on VSMC phenotype modulation.

Inhibitory Effect of Ginsenoside Rg1 on Vascular Smooth Muscle Cell Proliferation Induced by PDGF-BB Is Involved in Nitric Oxide Formation.

Ginsenoside Rg1 (Rg1) has been reported to suppress the proliferation of vascular smooth muscle cells (VSMCs). This study aimed to observe the role of nitric oxide (NO) in Rg1-antiproliferative effect. VSMCs from the thoracic aorta of SD rats were cultured by tissue explant method, and the effect of Rg1 (20 mg·L(-1), 60 mg·L(-1), and 180 mg·L(-1)) on platelet-derived growth factor-BB (PDGF-BB)-induced proliferation was evaluated by MTT assay. The cell cycle was analyzed by flow cytometry. For probing the mechanisms, the content of NO in supernatant and cGMP level in VSMCs was measured by nitric oxide kit and cGMP radio-immunity kit, respectively; the expressions of protooncogene c-fos and endothelial NO synthase (eNOS) mRNA in the VSMCs were detected by real-time RT-PCR; the intracellular free calcium concentration ([Ca2(+)](i)) was detected with Fura-2/AM-loaded VSMCs. Comparing with that in normal group, Rg1 180 mg·L(-1) did not change the absorbance of MTT and cell percent of G(0)/G(1), G(2)/M, and S phase in normal cells (P > 0.05). Contrarily, PDGF-BB could increase the absorbance of MTT (P < 0.01) and the percent of the S phase cells but decrease the G(0)/G(1) phase cell percent in the cell cycle, accompanied with an upregulating c-fos mRNA expression (P < 0.01), which was reversed by additions of Rg1(20 mg·L(-1), 60 mg·L(-1), and 180 mg·L(-1)). Rg1 administration could also significantly increase the NO content in supernatant and the cGMP level in VSMCs, as well as the eNOS mRNA expression in the cells, in comparison of that in the group treated with PDGF-BB alone (P < 0.01). Furthermore, Rg1 caused a further increase in the elevated [Ca(2+)](i) induced by PDGF-BB. It was concluded that Rg1 could inhibit the VSMC proliferation induced by PDGF-BB through restricting the G(0)/G(1) phase to S-phase progression in cell cycle. The mechanisms may be related to the upregulation of eNOS mRNA and the increase of the formation of NO and cGMP.

Ginsenoside Rg1 inhibits vascular intimal hyperplasia in balloon-injured rat carotid artery by down-regulation of extracellular signal-regulated kinase 2.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginsenoside Rg1 (Rg1) is one of the main active components of Panax ginseng a well-known herbal medicine. It has been demonstrated to inhibit proliferation of vascular smooth muscle cells (VSMCs) induced by tumor necrosis factor-αin vitro. The present study is aimed to examine the possible effects of Rg1 on vascular neointimal hyperplasia in balloon-injured carotid artery of rats in vivo. MATERIALS AND METHODS: The animal model was established by rubbing the endothelia with a balloon catheter in the common carotid artery (CCA) of male Sprague Dawley rats. Then the rats were intraperitoneally injected with distilled water in model group and sham operation control, or with Rg1 4, 8 and 16mg/kg/d in other balloon injured groups. After consecutive 14 days, the vascular intimal hyperplasia was evidenced by histopathological alterations of the CCA and by changes observed in the marker of the proliferation of VSMCs-the proliferating cell nuclear antigen (PCNA). The protein expressions of PCNA and the phosphorylated extracellular signal-regulated kinase2 (p-ERK2) as well as mitogen-ativated protein kinase phosphatase-1 (MKP-1) were examined by immunohistochemistry; while the expressions of proto-oncogene (c-fos), ERK2 and smooth muscle α-actin (SM α-actin) mRNA were analyzed by Real-Time RT-PCR. RESULTS: Rg1 administration could significantly ameliorate the histopathology of CCA and decrease the protein expression of PCNA induced by endothelia rubbing; and Rg1 medication also significantly decreased the expressions of p-ERK2 protein, ERK2 and c-fos mRNA in vessel wall, but up-regulated the MKP-1 expression, which was reported to inactivate mitogen-ativated protein kinase pathway. Furthermore, Rg1 could elevate the decreased SM α-actin mRNA expression induced by balloon injury. CONCLUSIONS: Rg1 can suppress the vascular neointimal hyperplasia induced by balloon injury, the mechanism may be involved in the inhibition on ERK2 signaling, and related, at least partly, to the increase in MKP-1 expression.

Total Ginsenosides suppress the neointimal hyperplasia of rat carotid artery induced by balloon injury.

Ginsenosides, the active components found in Panax ginseng, have been reported to inhibit the cardiac hypertrophy in rats. This study aims to observe the potential effect of total ginsenosides (TG) on the hypertrophic vascular diseases. The model of vascular neointimal hyperplasia was established by rubbing the endothelia of the common carotid artery with a balloon in male Sprague Dawley rats. TG (15 mg/kg/day, 45 mg/kg/day), L-arginine (L-arg) 200 mg/kg/day, and NG-nitro-L-arginine-methyl ester (L-NAME) 100 mg/kg/day used with the same dose of L-arg or TG 45 mg/kg/day were given for 7 and 14 consecutive days after surgery. TG and L-arg administrations significantly ameliorated the histopathology of injured carotid artery, which was abolished or blunted by L-NAME, an NOS inhibitor; TG and L-arg could also remarkably reduce the expression of proliferating cell nuclear antigen (PCNA), a proliferation marker of vascular smooth muscle cells(VSMCs), in neointima of the injured artery wall. Further study indicated that balloon injury caused a decreased superoxide dismutase (SOD) activity and an elevated malondialdehyde (MDA) content in plasma, and reduced the cGMP level in the artery wall, which were reversed by TG. It was concluded that TG suppress the rat carotid artery neointimal hyperplasia induced by balloon injury, which may be involved in its anti-oxidative action and enhancing the inhibition effects of NO/cGMP on VSMC proliferation.

Role of nitric oxide in ginsenoside Rg(1)-induced protection against left ventricular hypertrophy produced by abdominal aorta coarctation in rats.

Ginsenoside Rg(1) (Rg(1)), one of the active components of Panax ginseng, has been reported to promote endogenous nitric oxide (NO) production in some tissues, and to inhibit left ventricular (LV) hypertrophy in rats. This study aimed to investigate whether Rg(1)-induced inhibition of rat LV hypertrophy is mediated by NO-production. Rat LV hypertrophy was induced by abdominal aorta coarctation. Rg(1) 15 mg/kg/d, L-arginine 200 mg/kg/d, and the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine-methyl ester (L-NAME) 100 mg/kg/d used with the same dose of L-arginine or Rg(1) were given starting from 1 d after surgery for 21 consecutive days. LV hypertrophy was evidenced by determining LV weight and mRNA expression of atrial natriuretic peptide, a marker of cardiac hypertrophic response, as well as by histopathology. Rg(1) and L-arginine administration significantly reduced the elevated LV hypertrophic parameters independent of LV systolic pressure changing, and ameliorated the histopathology of LV myocardium and LV diastolic function. All the beneficial effects of Rg(1) and L-arginine were abolished or blunted by L-NAME. Further to examine the role of NO in Rg(1) inhibition on LV hypertrophy, expression of endothelial NOS was determined at the transcript levels. In our experimental conditions endothelial NOS mRNA expression in LV tissue was lowered by abdominal aorta coarctation, and upregulated by Rg(1) administration. These results demonstrate that Rg(1)-induced protection against LV hypertrophy elicited by abdominal aorta coarctation in rats is mediated, at least in part, via endogenous NO production and release.

Ginsenoside Rg(1) inhibits rat left ventricular hypertrophy induced by abdominal aorta coarctation: involvement of calcineurin and mitogen-activated protein kinase signalings.

Ginsenoside Rg(1) (Rg(1)), one of the active components of Panax ginseng, has been reported to inhibit proliferation of vascular smooth muscle cells induced by tumor necrosis factor-alpha. This study aims to investigate whether Rg(1) has protective effect on rat left ventricular hypertrophy and to probe its protective mechanisms. The rat left ventricular hypertrophy was induced by abdominal aorta coarctation and Rg(1) (3.75, 7.5 and 15 mg/kg/day) was given the day after surgery for 21 consecutive days. The left ventricular hypertrophy induced by abdominal aorta coarctation was evidenced by histopathology, electromicroscopy, and by determining the elevated left ventricular weight and the expression of atrial natriuretic peptide. Rg(1) significantly ameliorated left ventricular hypertrophy induced by abdominal aorta coarctation in a dose-dependent manner. To examine the mechanism of protection, the expressions of calcineurin, CnA (the catalytic subunit of calcineurin), extracellular signal-regulated kinase-1, and mitogen-activated protein (MAP) kinase phosphatase-1 were determined at the transcript and protein levels. The abdominal aorta coarctation induced increases in calcineurin, CnA, and extracellular signal-regulated kinase-1 expressions were suppressed, but the expression of MAP kinase phosphatase-1 was increased by Rg(1). These results demonstrate that Rg(1) alleviates left ventricular hypertrophy induced by abdominal aorta coarctation, and the protection appears to be due, at least in part, to its inhibitory effects on calcineurin and MAP kinase signaling pathways.

Protective effect of Ginkgo biloba leaf extract on learning and memory deficit induced by aluminum in model rats.

OBJECTIVE: To examine the protective effect of Ginkgo biloba leaf extract (GbE) on learning and memory deficit induced by aluminum chloride (AlCl(3)), and explore its mechanisms. METHODS: The rat models with learning and memory deficit were induced by administering via gastrogavage and drinking of AlCl(3) solution. And the model rats were treated with GbE at the dose of 50, 100, 200 mg/kg every day for 2 months accompanied with drinking of AlCl(3) solution, respectively. Their abilities of spatial learning and memory were tested by Morris water maze, and the acetylcholinesterase (AChE) activity in serum was assayed with chemical method, the AChE expression in hippocampus was observed by immunohistochemistry assay, and then quantitative analysis was done by BI 2000 image analysis system. RESULTS: Learning and memory deficit of rats could be induced by AlCl(3) solution (P < 0.01), and AChE expressions in rats hippocampus were increased (P < 0.01); GbE ameliorated learning and memory deficit and reduced AChE expression in rats hippocampus in a dose-dependent manner, while GbE significantly increased serum AChE activity at the dose of 200 mg/kg each day (P < 0.05). CONCLUSION: GbE can ameliorate learning and memory deficit induced by AlCl(3), which may be due to its inhibition of the AChE expression in hippocampus.

Protective effects of Ginkgo biloba leaf extract on aluminum-induced brain dysfunction in rats.

This study examined the protective effects of Ginkgo biloba extract (GbE) on the learning and memory function in aluminum-treated rats and potential mechanisms. Wistar rats were given daily aluminum chloride 500 mg/kg, i.g, for one month, followed by continuous exposure via the drinking water containing 1600 ppm aluminum chloride for up to 5 months. The ability of spatial learning and memory was tested by Morris water maze. Aluminum administration significantly increased escape latency and searching distance, indicative of brain dysfunction. GbE treatment (50-200 mg/kg, i.g) significantly protected against aluminum-induced brain dysfunction, as evidenced by decreased escape latency and searching distance compared with the Al alone group. To examine the mechanisms of the protection, the expressions of amyloid precursor protein (APP) and caspase-3 in brain regions were examined by immunohistochemistry. GbE treatment reduced the contents of APP and caspase-3 in hippocampus of aluminum-treated rats in a dose-dependent manner. At the highest dose of GbE (200 mg/kg), the immunostain for APP and caspase-3 was returned to normal levels. In summary, this study demonstrates that GbE is effective in improving the ability of spatial learning and memory of aluminum-intoxicated rats. This protection appears to be due to a decreased expression of APP and caspase-3 in rat brain, resulting in a decrease in the production of insoluble fragments of Abeta-amyloid.

Effects of protopine on intracellular calcium and the PKC activity of rat aorta smooth muscle.

We have previously shown that the vasodilator effect of protopine (Pro) on rabbit aorta is related to the elevations of cAMP and cGMP. In the present study, the vasodilator mechanisms of Pro were further explored by recording the isotonic contraction of the rat aortic strips, detecting directly the intracellular free Ca(2+) concentration ([Ca(2+)](i)) with Fura-2/AM loaded vascular smooth muscle cells (VSMCs) of rat aorta, and determining the activity of protein kinase C (PKC) in rat aortic tissue with radioactive isotope gamma-32P -ATP-catalyzing assay. By recording the aortic strips contraction induced by noradrenaline (NA) and high potassium (K(+)), Pro shifted nonparallelly the concentration-response curves of NA and high K(+) to right, in which the maximal response was depressed in the presence of Pro (30 and 100 micromol/L), and the values of pD'(2) were 3.70-/+0.25 and 3.97-/+0.15 for NA and high K(+), respectively. In the Fura-2/AM loaded VSMCs, Pro (50 and 100 micromol/L) could not produce any significant change on the resting [Ca(2+)](i), but significantly decreased the [Ca(2+)](i) elevated by NA and high K(+). Pro (30 and 100 micromol/L) had no significant effect on the activity of the cytosolic and membrane PKC in the aortic strips inpretreated by NA. However, in the aortic strips pretreated by NA, the activity of membrane PKC was significantly increased and the activity of cytosolic PKC tended to be decreased by Pro, while the activity of total PKC did not change. These results suggest that Pro seems to promote the translocation of PKC from the cytosol to the membrane in the presence of NA, its vasodilator effect may be the comprehensive result of its decreasing effect on the [Ca(2+)](i) and the increasing effect on cAMP and cGMP, as well as its influence on the PKC.

[Effect of ecdysterone on the expression of c-fos in the brain of rats induced by microinjection beta-AP25-35 into the hippocampus].

AIM: To observe the behavior in learning and memory and the expression of c-fos gene from the brain of rats induced by beta-AP25-35, and the intervention of ecdysterone, in order to explore the protective mechanism of ecdysterone on the dysfunction of learning and memory of the rat induced by beta-AP25-35. METHODS: Microinjection of beta-AP25-35 into hippocampus induced learning and memory dysfunction of rats. The learning and memory of rats were observed by Morris Water Maze. The expression of c-fos gene in the brain was detected by immunohistochemistry. RESULTS: The results of Morris Water Maze showed that after rats were microinjected beta-AP25-35 into hippocampus, the rats in model group took longer latency and searching distance compared with the ones in control group (P < 0.01), and the rats in treated group (ECR 4 mg x kg(-1), ECR 8 mg x kg(-1) and nimodipine 7.2 mg x kg(-1)) took shorter latency and searching distance, especially the ECR 8 mg kg(-1) group (P < 0.01). At the same time, after the 5 days training, there was a higher expression of c-fos in hippocampus and cortex from the rats in control group than that in model group (P < 0.01), but in the treated group, there was a relatively higher expression of c-fos, especially the ECR 8 mg x kg(-1) group (P < 0.01). CONCLUSION: Microinjection of beta-AP25-35 into the rat hippocampus resulted in dysfunction of learning and memory. Ecdysterone was shown to improve the learning and memory of the rats and increase the expression of c-fos. Increasing the expression of c-fos is probably one of the most molecular mechanism of its protection.